Spotty decoding of BASE64 parts

[sertys3]

Greetings,
thank you for the wonderful work thus far. I am running mail2deck for my NextCloud users successfully but since we're based in Eastern Europe, users send mail in cyrillic script which creates a confusion upon card creation. I am not so great at creating PRs and will describe the issue and fix in here. When sending via gmail, the body parts get base64 encoded upon detection of non-latin characters. This does reflect in the imap structure though. I have made small modification to index.php in the message processing as such :
Instead of

$base64encode = false;
if($structure->encoding == 3) {
    $base64encode = true; // BASE64
}

I have modified it to:

$base64encode = false;
if($structure->parts[0]->encoding == 3) {
    $base64encode = true; // BASE64
}
if(isset($structure->parts[0]->parts[0]->encoding) && $structure->parts[0]->parts[0]->encoding == 3){
   // this handles parts with inline attachments
    $base64encode = true; // BASE64
}

This correctly sets the $base64encode flag for the description and decodes the body characters correctly.
I hope you find the time to implement such a change for the non-latin users in the community.

Kindest regards,
Daniel